Oxygen concentrator



FIG. 1 is a front-right-top perspective view of an oxygen concentrator, showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is a perspective view showing an embodiment of the claimed design, wherein the broken lines are shown for illustrative purposes only and form no part of the claimed design. 

The ornamental design for an oxygen concentrator, as shown and described. 